EVIDENCE OF THE EXISTENCE OF HIGH-ALUMINA CLINOPYROXENE (TSCHERMAKITE) IN GARNET PYROXENITES FROM THE KOKCHETAV MASSIF, KAZAKHSTAN

Abstract

Our study showed that anorthite-zoisite-spinel/magnetite-corundum pseudomorphs in coronites of the Kokchetav Massif developed after high-alumina clinopyroxene (tschermakite) (Ca,Fe,Mg Al2SiO6. This phase is stable only at high PT parameters. Therefore, it can be replaced by aggregate of later minerals during retrograde metamorphism.